Typewriters are known that employ a ribbon carrying a polymeric ink film. The ribbon is equivalent to the ink ribbon used in a conventional typewriter and ink in the shape of a printing character is transferred from it onto a substrate (usually paper) not by impact but by a printing head that heats only the regions of the ribbon from which the ink is to be transferred to the paper. After a character has been printed, the typewriter carriage is advanced for printing the next character and the ribbon is advanced.
Such typewriters achieve high quality printing but are wasteful, and therefore costly to operate, because at the time that a ribbon needs to be discarded, most of its surface is still coated with ink that has not been transferred to a printing substrate.